TWI507584B - Process for the coating of textiles - Google Patents

Description

Method for coating fabric

The present invention is directed to a method of making a coated fabric wherein the fabric substrate is first contacted with an aqueous dispersion comprising at least one inorganic salt and at least one modified cellulose.

It has long been known to coat fabrics from plastic to make synthetic leather for a period of time. Synthetic leather is used, for example, as a shoe upper material, as a garment, as a bag making material or in the interior decoration industry. In addition to other plastics such as PVC, the primary coating material used herein is a polyurethane. It is generally known that the principle of coating fabrics with polyurethanes is described in W. Schr Er, Textilveredlung [Textile Finishing] 1987, 22 (12), 459-467. A description of the coagulation method can be found in "New Materials Permeable to Water Vapor", Harro Tr Ubel, Springer Verlag, Berlin, Heidelberg, New York, 1999, ISBN 3-540-64946-8, pages 42-63.

The main methods used in the manufacture of synthetic leather are direct coating, transfer coating (indirect coating), and coacervation (wet). The coating of the transfer method is applied to the temporary support as compared to the direct method, followed by a lamination step in which the film is bonded to the fabric substrate and separated by a temporary support (release paper). The transfer method is preferably a fabric substrate which does not allow high tensile stress during coating or a tissue which is not particularly dense.

In the coacervation process, the fabric substrate is typically coated with a solution containing a polyurethane in DMF. In the second step, the coated substrate is passed through a DMF/water bath in which the proportion of water is gradually increased. Here, the polyurethane precipitates and forms a microporous membrane. Here, the following facts are utilized: DMF and water have excellent mutual solubility and DMF and water are used as solvent/non-solvent pairs of polyurethanes. High quality synthetic leathers are particularly coated with agglomerated polyurethanes because of their relatively good breathing activity and leather feel. The basic principle of the coacervation method is based on the use of a suitable solvent/non-solvent pair of polyurethanes. The greatest advantage of the coacervation method is the availability of microporous, breathable synthetic leather with excellent leather feel. Examples are (for example) synthetic leather brand Clarino And Alcantara . The disadvantage of the coacervation method is that a large amount of DMF must be used as an organic solvent. In order to minimize the exposure of employees to DMF release during manufacturing, additional design measures must be taken, which is a significant increase over the simpler process representative. In addition, a large amount of DMF/water mixture must be discarded or disposed of. This is difficult because water and DMF form an azeotrope and therefore can only be separated by distillation by more effort.

It is therefore an object of the present invention to develop a method of coating a textile substrate which does not require the use of a toxicologically unacceptable solvent such as, for example, DMF, to obtain a coated article having good properties such as, for example, good feel. Cloth fabric.

This object has been achieved by a method of making a coated fabric comprising at least the following steps:

a) contacting the textile substrate with an aqueous dispersion A comprising at least one inorganic salt and at least one modified cellulose,

b) contacting the textile substrate with an aqueous dispersion B comprising a polyurethane, and

c) precipitating the polyurethane in or on the textile substrate.

In step a), the textile substrate is contacted with an aqueous solution comprising at least one inorganic salt and at least one modified cellulose.

The inorganic salt is preferably one selected from the group consisting of alkali metal salts and alkaline earth metal salts. The inorganic salt is preferably selected from the group consisting of alkali metal halides, alkali metal phosphates, alkali metal nitrates, alkali metal sulfates, alkali metal carbonates, alkali metal hydrogencarbonates, alkaline earth metal halides, alkaline earth metal nitrates, a salt of the group consisting of alkaline earth metal phosphates, alkaline earth metal sulfates, alkaline earth metal carbonates and alkaline earth metal hydrogencarbonates. The inorganic salt is particularly excellent in sodium chloride, potassium chloride, sodium sulfate, sodium carbonate, potassium sulfate, potassium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, magnesium chloride, magnesium sulfate, magnesium nitrate, calcium chloride, calcium nitrate or Calcium sulfate. The inorganic salt is more preferably calcium nitrate, magnesium nitrate, calcium chloride or magnesium chloride.

The inorganic salt is preferably present in an amount of from 0.01 to 25% by weight based on the total amount of the dispersion A, particularly preferably from 0.5 to 15% by weight, and most preferably from 0.5 to 10% by weight in the dispersion. A.

The chemically modified cellulose is preferably selected from the group consisting of alkylated cellulose, hydroxyalkylated cellulose, and carboxyalkylated cellulose.

The chemically modified cellulose is preferably selected from the group consisting of methyl cellulose, ethyl cellulose, propyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxymethyl cellulose, hydroxypropyl methyl cellulose. a compound of the group consisting of carboxymethylcellulose, carboxyethylcellulose, and carboxypropylcellulose.

Chemically modified cellulose is extremely preferred as methyl cellulose or ethyl cellulose.

The modified cellulose is preferably in an amount of from 10 ppm to 5% by weight based on the total amount of the dispersion A, particularly preferably from 100 ppm to 3% by weight, and most preferably from 400 ppm to 1.5% by weight. Dispersion A.

Preferably, the textile substrate is contacted with the aqueous dispersion A for 2 to 4 minutes at room temperature, particularly preferably for 1 to 2 minutes, and particularly preferably for 0.2 to 1 minute. For the purposes of the present invention, the contact is meant to be partially or completely impregnated, preferably completely immersed in the dispersion or by hand coating, printing and spray coating the dispersion.

After contacting the dispersion A, the fabric substrate is preferably passed through a wringer consisting of two rolls to remove excess dispersion A. Preferably, the wringer is set in such a manner that the residual amount of the dispersion A in the textile substrate is per unit area of the substrate before the substrate is contacted with the polyurethane-containing dispersion B. The weight (liquid absorption amount) is from 60 to 180% by weight, particularly preferably from 70 to 140% by weight, and particularly preferably from 80 to 120% by weight. The fabric substrate is preferably partially dried by air, infrared or hot roller for 2 to 10 minutes, preferably 1 to 5 minutes, before the fabric substrate can be contacted with the polyurethane-containing dispersion B.

The polyurethane present in the dispersion B is not particularly limited as long as it is soluble in water, and the term "polyurethane" also encompasses a polyurethane-polyurea. A review of polyurethane dispersions (PUR) dispersions and processes thereof can be found in Rosthauser & Nachtkamp, "Waterborne Polyurethanes, Advances in the Urethane Science and Technology", Vol. 10, pp. 121-162 (1987). Suitable dispersions are also described, for example, in "Kunststoffhandbuch" [Plastics Handbook], Vol. 7, 2nd Edition, Hauser, pages 24 to 26.

The composition of the dispersion B used in accordance with the present invention may be the following:

1) Organic di- and/or polyisocyanates such as, for example, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), 2-methylpentamethylene diisocyanate, 2,2,4-trimethyl Hexamethylene diisocyanate (THDI), dodecyl methylene diisocyanate, 1,4-diisocyanatocyclohexane, 3-isocyanatomethyl-3,3,5-trimethyl Cyclohexyl isocyanate (isophorone diisocyanate = IPDI), 4,4'-diisocyanatodicyclohexylmethane (Desmodur W), 4,4'-diisocyanato-3,3'-dimethyldicyclohexylmethane, 4,4'-diisocyanato-2,2-dicyclohexylpropane, 1,4 -diisocyanatobenzene, 2,4- or 2,6-diisocyanatotoluene or a mixture of such isomers, 4,4'-, 2,4- or 2,2'-diiso Cyanate diphenylmethane or a mixture of such isomers, 4,4-, 2,4'- or 2,2'-diisocyanato-2,2-diphenylpropane-p-di Toluene diisocyanate and a mixture of α,α,α',α'-tetramethyl-m- or-p-xylene diisocyanate (TMXDI) and the like. A small amount of the above-mentioned diisocyanate trimer, urethane, biuret, allophanate or ureidodione can be used for the purpose of upgrading. Very good for MDI, Desmodur W, HDI and/or IPDI.

2) Polyhydroxyl compounds having from 1 to 8, preferably from 1.7 to 3.5 hydroxyl groups and up to 16,000, preferably up to 4000 (average) molecular weight per molecule. Low molecular weight polyhydroxy compounds as defined in each case may be considered, such as, for example, ethylene glycol, 1,2-, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, new The reaction product of pentanediol, trimethylolpropane, glycerin, 1肼+2 propylene glycol and an oligomeric or polymeric hydroxy compound having a molecular weight of from 350 to 10,000, preferably from 840 to 3,000.

The relatively high molecular weight hydroxy compound includes a hydroxy polyester, a hydroxy polyether, a hydroxy polythioether, a hydroxypolyacetate, a hydroxypolycarbonate, and/or a hydroxypolyester amide, which are known per se by the urethane chemistry. Those having an average molecular weight of 350 to 4,000, and those having a mean molecular weight of 840 to 3,000. Particularly preferred are hydroxy polycarbonates and/or hydroxy polyethers. When such materials are used, agglomerates having specific hydrolytic stability can be obtained.

3a) an acid group containing an acid group and/or a salt form and at least one isocyanate-reactive group such as an OH or NH ₂ group ion or a latent ionic hydrophilic agent. Examples are sodium salt of ethylenediamine-β-ethylsulfonic acid (AAS salt solution), dimethylolpropionic acid (DMPA), dimethylolbutanoic acid, hydroxytrimethylacetic acid or 1 molar diamine Preferably, it is an adduct of the isophorone diamine and 1 mol of the α,β-unsaturated carboxylic acid, preferably acrylic acid.

3b) A mono- and/or difunctional polyethylene oxide or a nonionic hydrophilic agent in the form of a polyethylene-propylene oxide alcohol having a molecular weight of from 300 to 5,000. Particularly preferred are monohydroxy-functional ethylene oxide/propylene oxide polyethers having n-butanol as the main unit having 35 to 85% by weight of ethylene oxide units and having a molecular weight of 900 to 2,500. Preferably at least 3% by weight, in particular at least 6% by weight, of nonionic hydrophilic agent

4) Isocyanate-based blocking agents such as, for example, hydrazine (acetone oxime, butanone oxime or cyclohexanone oxime), secondary amines (diisopropylamine, dicyclohexylamine), NH-acid heterocyclic substances (3,5-dimethylpyrazole, imidazole, 1,2,4-triazole), CH-acid ester (C _1-4 -alkylmalonate, acetate) or indoleamine (ε) - caprolactam). Particularly preferred are butanone oxime, diisopropylamine and 1,2,4-triazole.

5) Polyamines as a built-in chain extender. Such materials include, for example, 6) the polyamines discussed. 3a) The diamine-functional hydrophilic agent in question is also suitable as the chain extender to be incorporated.

6) Polyamine crosslinker. While such materials may also employ trifunctional polyamines or polyfunctional polyamines to achieve specific properties, it is preferred to use aliphatic or cycloaliphatic diamines. In general, polyamines containing additional functional groups such as, for example, OH groups can be used. Polyamine crosslinkers that are not incorporated into the polymer backbone at normal or slightly elevated ambient temperatures, such as 20 to 60 °C, are mixed immediately during the preparation of the reactive dispersion or at subsequent time points. Examples of suitable aliphatic polyamines are ethylenediamine, 1,2- and 1,3-propanediamine, 1,4-tetramethylenediamine, 1,6-hexamethylenediamine, An isomeric mixture of 2,2,4- and 2,4,4-trimethylhexamethylenediamine, 2-methylpentamethylenediamine and diethylenetriamine.

In another preferred embodiment, dispersion B comprises at least one coagulant in addition to the polyurethane. A coagulant is a salt or an acid, such as an ammonium salt of an organic acid, which initiates agglomeration of the polyurethane under specific conditions, such as, for example, a particular temperature. Such materials include acid generating chemicals, ie, substances which are not acidic at room temperature but which become acidic after warming. Specific examples of such compounds include ethylene glycol diacetate, ethylene glycol formate, diethylene glycol formate, triethyl citrate, monostearyl citrate, and organic acid esters.

The coagulant is preferably present in the composition in an amount of from 1 to 10% by weight based on the solid content of the dispersion B.

The polyurethane present in the dispersion B is preferably an anionic and/or nonionic hydrophilized polyurethane which can be obtained by:

A) Preparation of isocyanate-functional prepolymers from the following

A1) Organic polyisocyanate

A2) a polymeric polyol having a number average molecular weight of from 400 to 8000 g/mole, preferably from 400 to 6000 g/mole, particularly preferably from 600 to 3000 g/mol, and from 1.5 to 6, preferably 1.8. Up to 3, the excellent OH functionality of 1.9 to 2.1 and

A3) a hydroxy-functional compound having a molecular weight of 32 to 400 g/mole, as appropriate

A4) an isocyanate-reactive anion or a potential anion and/or a non-ionic hydrophilic agent, as appropriate,

B) all or part of its free NCO group

B1) optionally with a compound having a molecular weight of from 32 to 400 g/mol of amino function and/or

B2) isocyanate-reactive, preferably amine-functional, anionic or potentially anionic hydrophilic agent

Subsequent reaction with the chain extender and the resulting prepolymer are dispersed in water before, during or after step B), wherein any of the potential ionic groups present are converted to the ionic form by partial or complete reaction with the neutralizing agent.

In order to achieve anionic hydrophilization, it is necessary to carry out A4) and/or B2) with a hydrophilic agent, wherein the hydrophilic agent comprises at least one pair of NCO-based reactive groups, such as an amine group, a hydroxyl group or a thiol group, and additionally comprises -COO ^- or -SO ₃ ^- or -PO ₃ ^2- as an anion or a fully or partially protonated acid form thereof as a potential anionic group.

The preferred aqueous anionic polyurethane dispersion (I) has a low hydrophilic anionic group, preferably from 0.1 to 15 milliequivalents per 100 grams of solid resin.

In order to obtain good deposition stability, the number average particle diameter of the specific polyurethane dispersion measured by laser correlation spectroscopy is preferably less than 750 nm, and particularly preferably less than 500 nm. It is less than 400 nm.

During the preparation of the NCO-functional prepolymer, the ratio of the NCO group in the compound of component A1) to the NCO reactive group in the compound of component A2) to A4), such as the ratio of amine group, hydroxyl group or thiol group 1.05 Up to 3.5, preferably from 1.2 to 3.0, particularly preferably from 1.3 to 2.5.

The amino-functional compound of step B) is used in an amount such that the equivalent ratio of the isocyanate-reactive amine group to the free isocyanate group in the prepolymer in the compound is from 40 to 150%, preferably from 50 to 125%. The best is 60 to 120%.

Suitable polyisocyanates of component A1) are aromatic, araliphatic, aliphatic or cycloaliphatic polyisocyanates which are known per se from the skilled artisan having an NCO functionality of 2.

Examples of suitable polyisocyanates of this type are 1,4-tert-butyl diisocyanate, 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 2, 2, 4- and / Or 2,4,4-trimethylhexamethylene diisocyanate, isomeric bis(4,4'-isocyanatocyclohexyl)methane or a mixture thereof with any desired isomer content, 1,4 - cyclohexyl diisocyanate, 1,4-phenylene diisocyanate, 2,4- and/or 2,6-methylphenylene diisocyanate, 1,5-anaphthyl diisocyanate, 2,2'- And/or 2,4'- and/or 4,4'-diphenylmethane diisocyanate, 1,3- and/or 1,4-bis(2-isocyanatopropan-2-yl)benzene ( TMXDI), 1,3-bis(isocyanatomethyl)benzene (XDI) and alkyl 2,6-diisocyanatohexanoate containing C ₁ -C ₈ -alkyl (isobutyl diisocyanate) ).

In addition to the above polyisocyanate, it is also possible to use a ureidodione, a trimeric isocyanate, a urethane, an allophanate, a biuret, an imine oxadi Diketone and/or oxa compound a diketone structure proportionally modified diisocyanate and an unmodified polyisocyanate containing more than 2 NCO groups per molecule, such as 4-isocyanatomethyloctane 1,8-diisocyanate (decane triisocyanate) or Triphenylmethane 4,4',4"-triisocyanate.

Preference is given to polyisocyanates or poly-types of the abovementioned types which contain only aliphatic and/or cycloaliphatic bonded isocyanate groups and have an average NCO functionality of from 2 to 4, preferably from 2 to 2.6, particularly preferably from 2 to 2.4. Isocyanate mixture.

Particularly preferred in A1) is 1,6-hexamethylene diisocyanate, isophorone diisocyanate, isomeric bis(4,4'-isocyanatocyclohexyl)methane, and mixtures thereof.

Based in A2) having a number average molecular weight M _n from 400 to 8000 g / mole, preferably 400 to 6000 g based / mole, particularly preferably 600 to 3,000 g based / mole of polymeric polyol. Preferably, it has an OH functionality of from 1.5 to 6, particularly preferably from 1.8 to 3, and very preferred from 1.9 to 2.1.

Polyester polyols, polyacrylate polyols, polyurethane urethanes, polycarbonate polyols, polyether polyols known per se in this type of polymeric polyol-based polyurethane coating technology , Polyester Polyacrylate Polyol, Polyurethane Polyacrylate Polyol, Polyurethane Polyester Polyol, Polyurethane Polyether Polyol, Polyurethane Polymer Carbonate polyols and polyester polycarbonate polyols. They can be used in A2) individually or in any desired mixture.

Polyester polyols of this type are known per se as poly-condensates of di- and tetra-alcohols with di- and optionally tri- and tetracarboxylic acids or hydroxycarboxylic acids or lactones. The corresponding polycarboxylic acid anhydride or the corresponding polycarboxylate for the preparation of the lower alcohol of the polyester may also be used in place of the free polycarboxylic acid.

Examples of suitable glycols are ethylene glycol, butylene glycol, diethylene glycol, triethylene glycol, polyalkylene glycols such as polyethylene glycol, and 1,2-propanediol, 1,3-propanediol, 1 , 3-butanediol, 1,4-butanediol, 1,6-hexanediol and isomers, neopentyl glycol or neopentyl glycol hydroxytrimethyl acetate, of which 1,6- Hexanediol and isomers, neopentyl glycol and neopentyl glycol hydroxytrimethyl acetate are preferred. Further, a polyhydric alcohol such as trimethylolpropane, glycerin, erythritol, pentaerythritol, trimethylolbenzene or trishydroxyethyltrimeric isocyanate may also be used.

Dicarboxylic acid phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid, sebacic acid , glutaric acid, tetrachlorophthalic acid, maleic acid, fumaric acid, isaconic acid, malonic acid, suberic acid, 2-methylsuccinic acid, 3,3-diethylpentyl Diacid and / or 2,2-dimethylsuccinic acid. The corresponding anhydride can also be used as the acid source.

As long as the average functionality of the polyol to be esterified is >2, it is also possible to use monocarboxylic acids such as benzoic acid and hexanecarboxylic acid.

Preferred acids are aliphatic or aromatic acids of the above type. It is particularly preferred to be adipic acid, isophthalic acid and, as appropriate, 1,2,4-benzenetricarboxylic acid.

The preparation of a polyester polyol having a terminal hydroxyl group may be accompanied by the use of a hydroxycarboxylic acid such as hydroxycaproic acid, hydroxybutyric acid, hydroxydecanoic acid, hydroxystearic acid, and the like as a reaction partner. Suitable lactones are caprolactone, butyrolactone and homologues. Preferred is caprolactone.

A hydroxyl-containing polycarbonate having a number average molecular weight M _{n of} from 400 to 8000 g/mole, preferably from 600 to 3000 g/mole, preferably a polycarbonate diol, can also be used in A2). Such materials can be obtained by reacting a carbonic acid derivative such as diphenyl carbonate, dimethyl carbonate or phosgene with a polyol, preferably a glycol.

Examples of this type of glycol are ethylene glycol, 1,2- and 1,3-propanediol, 1,3- and 1,4-butanediol, 1,6-hexanediol, 1,8-octane Alcohol, neopentyl glycol, 1,4-bishydroxymethylcyclohexane, 2-methyl1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, dipropylene glycol, Polypropylene glycol, dibutylene glycol, polytetramethylene glycol, bisphenol A, and a lactone modified by a lactone of the above type.

The polycarbonate diol preferably comprises 40 to 100% by weight of hexanediol, preferably 1,6-hexanediol and/or hexanediol derivative. This type of hexanediol derivative is based on hexanediol and additionally contains an ester or ether group in addition to the terminal OH group. Derivatives of this type can be obtained by the reaction of hexanediol with excess caprolactone or by the etherification of hexanediol with itself to obtain di- or tri-hexanediol.

Instead of or in addition to pure polycarbonate diols, polyether polycarbonate diols can also be used in A2).

The hydroxyl group-containing polycarbonate preferably has a linear structure.

Polyether polyols are also useful in A2).

Suitable polyether polyols are, for example, polyurethane chemistry which are known per se, which are obtained by polymerizing tetrahydrofuran by cationic ring opening.

Also suitable polyether polyols are known per se by the addition of styrene, ethylene oxide, propylene oxide, butylene oxide and/or epichlorohydrin to di- or polyfunctional starting molecules. It is also possible to use, as component A4) (nonionic hydrophilic agent), a polyether polyol which is at least proportionally added to the di- or polyfunctional starting molecule based on ethylene oxide.

Suitable starting compounds are all compounds known from the prior art, such as, for example, water, butyl diglycol, glycerol, diethylene glycol, trimethylolpropane, propylene glycol, sorbitol Ethylenediamine, triethanolamine, 1,4-butanediol. Preferred starting molecules are water, ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol and butyl diethylene glycol.

A particularly preferred embodiment of the polyurethane dispersion (I) comprises a mixture of a polycarbonate polyol and a polybutanediol polyol as component A2), wherein the proportion of the polycarbonate polyol in the mixture It is 20 to 80% by weight, and the ratio of the polybutanediol polyol is 80 to 20% by weight. The polybutanediol polyol in a ratio of 30 to 75% by weight and the polycarbonate polyol in a ratio of 25 to 70% by weight are preferred. It is particularly preferred to use a polybutanediol polyol in a ratio of from 35 to 70% by weight and a polycarbonate polyol in a proportion of from 30 to 65% by weight, in each case conditional polycarbonate polyol and polybutadiene The sum of the weight percentages of the diol polyol is 100% and the ratio of the sum of the polycarbonate polyol to the polybutanediol polyol in the component A2) is at least 50% by weight, preferably 60% by weight, particularly preferably It is at least 70% by weight.

The compound of component A3) has a molecular weight of from 62 to 400 g/mol.

A polyol having up to 20 carbon atoms in the molecular weight range such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1, 4 may be used in A3). -butanediol, 1,3-butanediol, cyclohexanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, neopentyl glycol, hydroquinone dihydroxyethyl ether, double Phenol A (2,2-bis(4-hydroxyphenyl)propane), hydrogenated bisphenol A (2,2-bis(4-hydroxycyclohexyl)propane), trimethylolpropane, glycerol, neopentyl alcohol And any mixture of their desires.

Also suitable for ester diols in the molecular weight range, such as α-hydroxybutyl-ε-hydroxycaproate, ω-hydroxyhexyl-γ-hydroxybutyrate, β-hydroxyethyl adipate or --hydroxyethyl terephthalate.

Further, a monofunctional isocyanate-reactive hydroxyl-containing compound can also be used in A3). Examples of monofunctional compounds of this type are ethanol, n-butanol, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, propylene glycol Monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, dipropylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, 2-ethyl Hexanol, 1-octanol, 1-dodecanol, 1-hexadecanol.

Preferred compounds of component A3) are 1,6-hexanediol, 1,4-butanediol, neopentyl glycol and trimethylolpropane.

The anionic or potentially anionic hydrophilic compound of component A4) means that all comprise at least one isocyanate-reactive group, such as a hydroxyl group and at least one functionality, such as, for example, -COO ^- M ⁺ , -SO ₃ ^- M ⁺ , -PO a compound of (O ^- M ⁺ ) ₂ wherein M ⁺ is, for example, a metal cation, H ⁺ , NH ₄ ⁺ , NHR ₃ ⁺ , wherein R may in each case be C ₁ -C ₁₂ -alkyl, C ₅ a -C ₆ -cycloalkyl group and/or a C ₂ -C ₄ -hydroxyalkyl group which, upon interaction with an aqueous medium, enters a pH-dependent dissociation equilibrium and can be negatively charged or neutral in this manner. Suitable anionic or potentially anionic hydrophilic compounds are mono- and dihydroxycarboxylic acids, mono- and dihydroxy sulfonic acids, and mono- and dihydroxy phosphonic acids and salts thereof. This type of anionic or potentially anionic hydrophilizing agent instance-based dimethylolpropionic acid, dimethylolbutyric acid, hydroxypivalic acid, malic acid, citric acid, glycolic acid, lactic acid and 2-butylene and NaHSO ₃ A propoxylated adduct as described in DE-A 2 446 440, pp. 5-9, Formula I-III. Preferred anionic or potentially anionic hydrophilic agents of component A4) are those having a carboxylate or carboxylic acid group and/or a sulfonate group as described above.

a particularly preferred anionic or potentially anionic hydrophilic agent A4), such as dimethylolpropionic acid, dimethylolbutanoic acid and hydroxytrimethylacetic acid, or a carboxylic acid radical or a carboxylic acid group thereof, or Salt.

Suitable nonionic hydrophilic compounds of component A4), for example, comprise at least a hydroxyl or amine group, preferably a polyoxyalkylene ether of at least one hydroxyl group.

An example is a monohydroxy-functional polyalkylene oxide polyether alcohol having a statistical average of from 5 to 70, preferably from 7 to 55, ethylene oxide units per molecule, as is known per se by suitable starting molecular alkane Oxidation is available (eg in Ullmann Encyclop Die der technischen Chemie [Ullmann's Encyclopedia of Industrial Chemistry], 4th edition, Vol. 19, Verlag Chemie, Weinheim, pp. 31-38).

It is a pure polyethylene oxide ether or a mixed polyalkylene oxide ether comprising at least 30 mol%, preferably at least 40 mol% of ethylene oxide units, based on all alkylene oxide units present. .

A particularly preferred nonionic compound is a monofunctional mixed polyalkylene oxide polyether containing 40 to 100 mole % of ethylene oxide units and 0 to 60 mole % of propylene oxide units.

Suitable starting molecules for this type of nonionic hydrophilic agent are saturated unit alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, second butanol, isomeric pentanol, hexanol, Octanol and decyl alcohol, n-nonanol, n-dodecanol, n-tetradecyl alcohol, n-hexadecanol, n-octadecyl alcohol, cyclohexanol, isomeric methylcyclohexanol or hydroxymethyl ring Hexane, 3-ethyl-3-hydroxymethyl propylene oxide or tetrahydrofuranol, diethylene glycol monoalkyl ether such as, for example, diethylene glycol monobutyl ether, unsaturated alcohol such as allyl alcohol 1,1-dimethylallyl or oleyl alcohol, aromatic alcohols such as phenols, isomeric cresols or methoxyphenols, araliphatic alcohols such as benzyl alcohol, araginol or cinnamyl alcohol a secondary monoamine such as dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, bis(2-ethyl-hexyl)amine, N-methyl- and N-ethylcyclohexylamine or dicyclohexylamine and heterocyclic secondary amines such as morphine, pyrrolidine, piperidine or 1H-pyrazole. Preferred starting molecules are saturated unit alcohols of the above type. Tetraethylene glycol monobutyl ether or n-butanol is used as a starting molecule.

Suitable alkylene oxides for alkoxylation are, in particular, ethylene oxide and propylene oxide, which can be used in the alkoxylation reaction in any desired order or also in a mixture.

Di- or polyamines such as 1,2-ethylenediamine, 1,2- and 1,3-diaminopropane, 1,4-diaminobutane, 1,6-diaminogen can be used. a mixture of isomers of alkane, isophorone diamine, 2,2,4- and 2,4,4-trimethylhexamethylenediamine, 2-methylpentamethylenediamine, diethylene Triamine, triamine decane, 1,3- and 1,4-decyldiamine, α,α,α',α'-tetramethyl-1,3-and-1,4-extension As the component B1), a diamine and 4,4-diaminodicyclohexylmethane and/or dimethylethylenediamine. You can also use 肼 or 醯肼, such as 醯肼. Preferred are isophorone diamine, 1,2-ethylenediamine, 1,4-diaminobutane, anthracene and diethylenetriamine.

Further, a compound containing a secondary amine group in addition to the primary amine group or an OH group in addition to the amine group (first or second stage) can also be used as the component B1). Examples thereof are primary/secondary amines such as diethanolamine, 3-amino-1-methylaminopropane, 3-amino-1-ethylaminopropane, 3-amino-1-cyclohexylamino group Propane, 3-amino-1-methylaminobutane, alkanolamines such as N-aminoethylethanolamine, ethanolamine, 3-aminopropanol, neopentylamine.

In addition, monofunctional isocyanate-reactive amine-based compounds such as, for example, methylamine, ethylamine, propylamine, butylamine, octylamine, laurylamine, stearylamine, isodecyloxy can also be used. Propylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, N-methylaminopropylamine, diethyl(methyl)aminopropylamine, morphine , piperidine or its suitable substituted derivatives, guanamine amines made from diprimary amines and monocarboxylic acids, monoketones of primary amines, primary/ tertiary amines For example, N,N-dimethylaminopropylamine is used as component B1).

Preferred compounds of component B1) are 1,2-ethylenediamine, 1,4-diaminobutane and isophoronediamine.

The anionic or potentially anionic hydrophilic compound of component B2) means that all comprise at least one isocyanate-reactive group, preferably an amine group and at least one functionality, such as, for example, -COO ^- M ⁺ , -SO ₃ ^- M ⁺ a compound of -PO(O ^- M ⁺ ) ₂ wherein M ⁺ is, for example, a metal cation, H ⁺ , NH ₄ ⁺ , NHR ₃ ⁺ , wherein R may in each case be a C ₁ -C ₁₂ -alkyl group C ₅ -C ₆ -cycloalkyl and/or C ₂ -C ₄ -hydroxyalkyl, which, upon interaction with an aqueous medium, enter a pH-dependent dissociation equilibrium and can be negatively charged or neutral in this manner.

Suitable anionic or potentially anionic hydrophilic compounds are mono- and diaminocarboxylic acids, mono- and diaminosulfonic acids, and mono- and diaminophosphonic acids and salts thereof. Examples of anionic or potentially anionic hydrophilic agents of this type are N-(2-aminoethyl)-β-alanine, 2-(2-aminoethylamino)-ethanesulfonic acid, ethylenediamine-propyl Base- or butyl sulfonic acid, 1,2- or 1,3-propanediamine-β-ethyl sulfonic acid, glycine, alanine, taurine, lysine, 3,5-diamine Benzoic acid and the addition reaction product of IPDA and acrylic acid (EP-A 0 916, example 1). Furthermore, cyclohexylaminopropane sulfonic acid (CAPA) known from WO-A 01/88006 can be used as an anionic or potentially anionic hydrophilic agent.

Preferred anionic or potentially anionic hydrophilic compounds of component B2) are those having a carboxylate or carboxylic acid group and/or a sulfonate group, such as N-(2-aminoethyl)-β-alanine, a salt of 2-(2-aminoethylamino)-ethanesulfonic acid or an addition reaction product of IPDA with acrylic acid (EP-A 0 916 pursuant to Example 1).

The hydrophilization can also be carried out using a mixture of an anionic or potentially anionic hydrophilic agent and a nonionic hydrophilic agent.

In a preferred embodiment for preparing a particular polyurethane dispersion, the following amounts of components A1) to A4) and B1) to B2) are used, wherein the sum of the individual amounts is always 100% by weight: 5 to 40 % by weight of component A1), 55 to 90% by weight of component A2), 0.5 to 20% by weight of the sum of components A3) and B1), 0.1 to 25% by weight of the sum of components A4) and B2) Wherein from 0.1 to 5% by weight, based on the total of components A1) to A4) and B1) to B2), an anionic or potentially anionic hydrophilic agent selected from the group consisting of A4) and/or B2).

In a particularly preferred embodiment for preparing a particular polyurethane dispersion, the following amounts of components A1) to A4) and B1) to B2) are used, wherein the sum of the individual amounts is always 100% by weight: 5 to 35 % by weight of component A1), 60 to 90% by weight of component A2), 0.5 to 15% by weight of the sum of components A3) and B1), 0.1 to 15% by weight of the sum of components A4) and B2) Wherein from 0.2 to 4% by weight, based on the total of components A1) to A4) and B1) to B2), an anionic or potentially anionic hydrophilic agent selected from the group consisting of A4) and/or B2).

In a very preferred embodiment for the preparation of a specific polyurethane dispersion, the following amounts of components A1) to A4) and B1) to B2) are used, wherein the sum of the individual amounts is always 100% by weight: 10 to 30% by weight of component A1), 65 to 85% by weight of component A2), 0.5 to 14% by weight of component A3) and B1), 0.1 to 13.5% by weight of component A4) and B2) The sum wherein 0.5 to 3.0% by weight of an anionic or potentially anionic hydrophilic agent selected from A4) and/or B2) is used, based on the total of components A1) to A4) and B1) to B2).

The preparation of the anionically hydrophilized polyurethane dispersion (I) can be carried out in one or more steps in a homogeneous or multi-step reaction, in part in a dispersed phase. After the complete or partial polyaddition of A1) to A4), a dispersion, emulsification or dissolution step is carried out. If necessary, another polyaddition or modification is then carried out in the dispersed phase.

All methods known from the prior art can be utilized herein, such as, for example, prepolymer blending, acetone or melt dispersion. It is preferred to use an acetone method.

For the preparation by the acetone method, the components A2) to A4) and the polyisocyanate component A1) are usually introduced in whole or in part to prepare an isocyanate-functional polyurethane prepolymer and, if appropriate, water-miscible but The isocyanate group is diluted with an inert solvent and then heated to a temperature ranging from 50 to 120 °C. In order to accelerate the isocyanate addition reaction, a catalyst known in the art of polyurethane chemistry can be used.

Suitable solvents are solvents which are customary in the aliphatic ketone function, such as acetone, 2-butanone, which can be added at the beginning of the preparation and, if necessary, later in portions. Preferred are acetone and 2-butanone.

Other solvents may be additionally used, such as xylene, toluene, cyclohexane, butyl acetate, methoxypropyl acetate, N-methylpyrrolidone, N-ethylpyrrolidone, ether or ester units The solvent can be completely or partially distilled or left completely in the dispersion in the case of N-methylpyrrolidone or N-ethylpyrrolidone. However, it is preferred not to use other solvents which are not customary aliphatic ketone functional solvents.

Then, any component which has not been added at the beginning of the reaction in A1) to A4) is metered.

When the polyurethane prepolymer is prepared from A1) to A4), the isocyanate-reactive isocyanate-reactive group has a molar ratio of from 1.05 to 3.5, preferably from 1.2 to 3.0, particularly preferably from 1.3 to 2.5.

The components A1) to A4) are converted into part or all of the prepolymer system, but are preferably all carried out. Thus, the polyurethane prepolymer comprising free isocyanate groups is obtained in solid form or in solution.

Partial or complete conversion of the latent anionic group to an anionic group. The neutralization step uses a base such as a tertiary amine such as 1 to 12 C atoms, preferably 1 to 6 C atoms in each alkyl group, particularly preferably 2 Up to 3 C atoms of a trialkylamine or an alkali metal base, such as a corresponding hydroxide.

Examples thereof are trimethylamine, triethylamine, methyldiethylamine, tripropylamine, N-methylmorpholine, methyldiisopropylamine, ethyldiisopropylamine and Isopropyl ethylamine. The alkyl group may also carry, for example, a hydroxyl group such as a dialkyl monoalkanolamine, an alkyl dialkanolamine, and a trialkanolamine. The neutralizing agent can also be an inorganic base if necessary, such as an aqueous ammonia solution or sodium hydroxide or potassium hydroxide.

Preferred are ammonia, triethylamine, triethanolamine, trimethylethanolamine or diisopropylethylamine, and sodium hydroxide and potassium hydroxide, particularly preferably sodium hydroxide and potassium hydroxide.

The molar amount of the base is from 50 to 125 mol%, preferably from 70 to 100 mol%, of the molar amount of the acid group to be neutralized. If the dispersing water already contains a neutralizing agent, the neutralization can also be carried out simultaneously with the dispersing.

In a further process step, the resulting prepolymer is then dissolved by means of an aliphatic ketone, such as acetone or 2-butanone, if this has not been done or only partially carried out.

In Step B) in the chain elongation, NH ₂ - and / or NH- functional component of the prepolymer remaining in the isocyanate moiety or a complete reaction. Chain elongation/termination is preferably carried out prior to dispersion in water.

For chain termination, an amine containing an isocyanate-reactive group, such as methylamine, ethylamine, propylamine, butylamine, octylamine, laurylamine, stearylamine, isodecyloxypropyl, is usually used. Amine, dimethylamine, diethylamine, dipropylamine, dibutylamine, N-methylaminopropylamine, diethyl(methyl)aminopropylamine, morphine, piperazine Pyridine or a substituted derivative thereof, a mercaptoamine prepared from a dibasic amine and a monocarboxylic acid, a monoimine of a dibasic amine, a primary/ tertiary amine such as N,N-dimethyl Aminopropylamine.

If partial or complete chain elongation is carried out using an anion or a potential anionic hydrophilic agent containing NH ₂ or NH groups corresponding to definition B 2), the chain elongation of the prepolymer is preferably carried out prior to dispersion.

The amine components B1) and B2) can optionally be used in the process according to the invention, either individually or in the form of a mixture, either in water or in solvent dilution, wherein any order of addition is possible in principle.

If water or an organic solvent is used together as a diluent, the content of the diluent in the component for chain elongation in B) is preferably from 70 to 95% by weight.

Dispersion is preferably carried out after the chain has been elongated. For this purpose, the dissolved and chain-extended polyurethane polymer is optionally introduced into the dispersed water with high shear, such as, for example, vigorous stirring, or conversely, the dispersed water is stirred into the chain-extended polyamine group. In the formate polymer solution. Preferably, water is added to the polyurethane chain polymer having dissolved chain elongation.

The solvent still present in the dispersion after the dispersion step is usually removed by distillation. Removal during dispersion is equally feasible.

The residual content of the organic solvent in the polyurethane dispersion (I) is generally less than 1.0% by weight based on the entire dispersion.

The pH of the polyurethane dispersion (I) which is indispensable in the present invention is generally less than 9.0, preferably less than 8.5, particularly preferably less than 8.0, and particularly preferably from 6.0 to 7.5.

The solid content of the polyurethane dispersion (I) is 40 to 70% by weight, preferably 50 to 65% by weight, particularly preferably 55 to 65% by weight.

In another preferred embodiment, the dispersion B also contains a coagulant (II) in addition to the anionically hydrophilized polyurethane.

The coagulant (II) which can be used in the composition is all organic compounds having at least 2 cationic groups, preferably all cationic flocculants and precipitants known in the prior art, such as poly[2-(N, N, N). -trimethylamino)ethyl acrylate], polyethylenimine, poly[N-(dimethylaminomethyl)-propenylamine], substituted acrylamide, substituted methacryl a cationic homopolymer or copolymer of a salt of an amine, N-vinylformamide, N-vinylacetamide, N-vinylimidazole, 2-vinylpyridine or 4-vinylpyridine.

Preferably, the coagulant (II) is a cationic copolymer of acrylamide containing a structural unit of the formula (2), and particularly preferably comprises a structural unit of the formula (1) and a propylene of the structural unit of the formula (2) Cationic copolymer of guanamine:

Wherein R is C=O, -COO(CH ₂ ) ₂ - or -COO(CH ₂ ) ₃ - and X ^- -based halide, preferably a cationic coagulant (II) for use in chlorides. This type is a polymer having a number average molecular weight of from 500,000 to 50,000,000 g/mole.

This type of coagulant (II) is based, for example, on Praestol The trade name (Degussa Stockhausen, Krefeld, DE) sells flocculants as sewage sludge. Praestol The preferred type of coagulant is Praestol K111L, K122L, K133L, BC 270L, K144L, K166L, BC 55L, 185K, 187K, 190K, K222L, K232L, K233L, K234L, K255L, K332L, K333L, K334L, E 125, E 150 and mixtures thereof. Very good coagulant is Praestol 185K, 187K and 190K and mixtures thereof.

Dispersion B preferably comprises at least one pigment.

The manner in which it is precipitated in or on the textile substrate is largely dependent on the chemical composition of the dispersion B used in accordance with the present invention and is particularly dependent on the type of coagulant present. For example, precipitation can be carried out by condensation or by agglomeration of a salt, an acid or an electrolyte.

In general, precipitation is achieved by an increase in temperature. For example, the fabric substrate can be briefly heat treated by steam, for example at 100 to 110 ° C for 1 to 10 seconds. This is especially preferred if an ammonium salt or an organic acid is used as the coagulant. On the other hand, if the above-mentioned acid-forming chemical is used as a coagulant, the precipitation is preferably carried out as described in US Pat. No. 5,916,636, US Pat. No. 5,968,597, US Pat. No. 5,952,413, and US Pat.

Alternatively, the coacervate is caused by immersion in a salt solution. The aggregation is preferably carried out using an inorganic salt selected from the group consisting of alkali metal salts and alkaline earth metal salts. The inorganic salt is preferably selected from the group consisting of alkali metal halides, alkali metal nitrates, alkali metal phosphates, alkali metal sulfates, alkali metal carbonates, alkali metal hydrogencarbonates, alkaline earth metal halides, alkaline earth metal phosphates, a salt of the group consisting of alkaline earth metal nitrate, alkaline earth metal sulfate, alkaline earth metal carbonate and alkaline earth metal hydrogencarbonate: The inorganic salt is particularly preferably sodium chloride, potassium chloride, sodium sulfate, sodium carbonate, potassium sulfate, potassium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, magnesium chloride, magnesium sulfate, calcium chloride or calcium sulfate. The inorganic salt is more preferably calcium chloride or magnesium chloride.

The inorganic salt is preferably present in the salt solution in an amount of from 1 to 25% by weight, particularly preferably from 1 to 15% by weight, based on the total amount of the salt solution, in an amount of from 1 to 10% by weight.

After the precipitation of step c), other steps such as drying or condensation are carried out as necessary.

The fabric substrate used is preferably a woven fabric, a knitted fabric or a non-woven fabric based on natural and/or rayon. The woven substrate is particularly preferably a non-woven fabric (staple nonwoven, microfiber non-woven or the like).

The fabric substrate may preferably be polyester, nylon (6 or 66), cotton, polyester/cotton blend, wool, ramie, elastic yarn, glass, thermoplastic polyurethane (TPU), thermoplastic olefin ( The fiber composition of TPO) or the like. The fabric substrate can have a joined/mesh (woven), woven or non-woven construction.

The textile substrate can be treated with dyes, colorants, pigments, UV absorbers, plasticizers, soil redeposition agents, lubricants, antioxidants, flame retardants, rheological agents, and the like, before or after coating, However, it is preferred to carry out this addition before coating.

If the defined non-woven fabric is impregnated and coagulated by the elastomeric polymer and then subjected to a general coloring process, a suede-like synthetic leather having good color developing properties can be obtained.

The invention thus additionally relates to coated fabrics obtained according to the process of the invention, preferably synthetic leather.

Instance

Dispersion A has the following composition:

Ca(NO ₃ ) ₂ 80 pbw

Methyl cellulose 0.4 pbw

Water 920 pbw

The dispersion B1 for salt coacervation has the following composition:

Impranil 1380 1000 pbw

Water 5000 pbw

A method of preparing a coated fabric using salt agglomeration is depicted in FIG.

The dispersion B2 for thermal coacervation has the following composition:

Impranil DLU 100 pbw

Coagulant WS 20 pbw

EmulvinWA 20 pbw

Water 5000 pbw

A method of making a coated fabric using thermal coacervation is depicted in Figure 2.

The substrate which has been subjected to this process without contact with the dispersion A has a very rigid touch. Conversely. The substrate that has been treated in accordance with the present invention exhibits a pleasant soft rounded feel. When the obtained substrate is subsequently coated, the difference between the substrate treated by the dispersion A and the untreated substrate is also apparent, and the crease of the sharp and/or foaming is revealed in the case of the untreated coagulant. fold). The substrate treated in accordance with the present invention exhibits a round, optically perfect crease.

Figure 1 is a method of preparing a coated fabric by salt agglomeration.

Figure 2 is a method of making a coated fabric using thermal coagulation.

Claims (11)

A method of making a coated fabric comprising at least the steps of: a) contacting a textile substrate with an aqueous dispersion A comprising at least one inorganic salt and at least one modified cellulose, b) fabricating the substrate with The aqueous dispersion B of the polyurethane is contacted, and c) the polyurethane is precipitated in or on the textile substrate. The method of claim 1, wherein the inorganic salt is selected from the group consisting of alkali metal salts and alkaline earth metal salts. The method of claim 2, wherein the alkali metal salt is selected from the group consisting of an alkali metal halide, an alkali metal nitrate, an alkali metal phosphate, an alkali metal sulfate, an alkali metal carbonate, and an alkali metal hydrogencarbonate. The salt of the group. The method of claim 2, wherein the alkaline earth metal salt is selected from the group consisting of an alkaline earth metal halide, an alkaline earth metal nitrate, an alkaline earth metal phosphate, an alkaline earth metal sulfate, an alkaline earth metal carbonate, and an alkaline earth metal hydrogencarbonate. The salt of the group. The method of claim 1, wherein the inorganic salt is present in the dispersion A in an amount of from 0.01 to 25% by weight based on the total amount of the dispersion A. The method of claim 1, wherein the modified cellulose is selected from the group consisting of methyl cellulose, ethyl cellulose, propyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl group. a compound of the group consisting of cellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, carboxyethylcellulose, and carboxypropylcellulose. The method of claim 1, wherein the modified cellulose is present in the dispersion A in an amount of 10 ppm to 5% by weight based on the total amount of the dispersion A. The method of claim 1, wherein the fabric substrate used is a woven fabric, a knitted fabric or a non-woven fabric based on natural and/or rayon. The method according to item 1 of the patent application, characterized in that the polyurethane is precipitated in the aqueous bath of step c) or when the temperature ranges from 80 to 120 ° C. A coated fabric obtainable by the method according to claims 1 to 9. A coated fabric according to claim 10, characterized in that the coated fabric is a synthetic leather.